1. Field of the Invention
The present invention relates, in general, to a method and apparatus for recording data on an optical disc.
2. Description of the Related Art
Recently, an optical disc, on which video data having high image quality and audio data having high sound quality can be recorded, for example, a write-once Digital Versatile Disc (for example: DVD-R), or a rewritable DVD (for example: DVD-RW), and an optical disc device capable of recording/reproducing data on/from such an optical disc, have been widely popularized.
When data is recorded on an optical disc, an optical disc device accesses a predetermined area in the optical disc, for example, a Power Calibration Area (PCA), and performs an Optimum Power Control (OPC) operation, thus detecting the optimum recording power for recording.
When the recording speed requested by a user is, for example, ×4 speed, the optical disc device detects the optical power value suitable for ×4 speed-recording by accessing an inner PCA and performing an OPC operation at ×4 speed.
Further, when the recording speed requested by a user is faster than ×4 speed, for example, ×16 speed, the optical disc device detects an optical power value suitable for ×4 speed-recording by performing an OPC operation in an inner PCA, and thus detects an optical power value suitable for ×16 speed-recording by accessing an outer PCA and performing an OPC operation at ×16 speed, as shown in FIG. 1.
Thereafter, the optical disc device calculates an optical power value suitable for each recording speed or a current recording position (diameter) using the optical power values suitable for ×4 speed and ×16 speed, which are detected through the OPC operations performed in the inner PCA and the outer PCA, and thus performs a data recording operation using the optical power value.
Meanwhile, when the user of an optical disc device requests the recording of an external input signal or a broadcasting signal, the optical disc device first performs an OPC operation. Input data or the data encoded by a Moving Picture Experts Group (MPEG) encoder is temporarily stored in buffer memory, such as Random Access Memory (RAM) provided in the device, during the performance of the OPC operation.
In this case, the required capacity of the RAM is proportional to the time required to perform an OPC operation and recording resolution for data, and thus large-capacity RAM is required when the time required for the OPC operation is long or when the resolution of the data to be recorded is of High Quality (HQ). For example, RAM having a 64 MB or larger capacity must be used to buffer all High Quality (HQ) data for the period of about 6 seconds, which is the time required to perform the OPC operation.
Then, since RAM is relatively expensive, there occurs a problem in that, when large-capacity RAM is used, the cost of manufacturing the optical disc device inevitably increases, and thus it becomes difficult to reduce the manufacturing cost associated with the optical disc device.